This behavior is caused by a bug in Advanced Installer. Thank you for bringing this to our attention. A bugfix will be included in a future version (the next version will be released soon, so most likely the version after it). Until then the workaround is to press Alt+F twice.
Which version of Advanced Installer are you using?
I have tested this now with the latest version of Advanced Installer (16.2) and by pressing the ALT+F buttons combination, the drop-down menu is spawned.